1 /*
2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.security;
27
28 import java.util.*;
29
30 import java.security.Provider.Service;
31 import java.security.spec.KeySpec;
32 import java.security.spec.InvalidKeySpecException;
33
34 import sun.security.util.Debug;
35 import sun.security.jca.*;
36 import sun.security.jca.GetInstance.Instance;
37
38 /**
39 * Key factories are used to convert <I>keys</I> (opaque
40 * cryptographic keys of type {@code Key}) into <I>key specifications</I>
41 * (transparent representations of the underlying key material), and vice
42 * versa.
43 *
44 * <P> Key factories are bi-directional. That is, they allow you to build an
45 * opaque key object from a given key specification (key material), or to
46 * retrieve the underlying key material of a key object in a suitable format.
47 *
48 * <P> Multiple compatible key specifications may exist for the same key.
49 * For example, a DSA public key may be specified using
50 * {@code DSAPublicKeySpec} or
51 * {@code X509EncodedKeySpec}. A key factory can be used to translate
52 * between compatible key specifications.
53 *
54 * <P> The following is an example of how to use a key factory in order to
55 * instantiate a DSA public key from its encoding.
56 * Assume Alice has received a digital signature from Bob.
57 * Bob also sent her his public key (in encoded format) to verify
58 * his signature. Alice then performs the following actions:
59 *
60 * <pre>
61 * X509EncodedKeySpec bobPubKeySpec = new X509EncodedKeySpec(bobEncodedPubKey);
62 * KeyFactory keyFactory = KeyFactory.getInstance("DSA");
63 * PublicKey bobPubKey = keyFactory.generatePublic(bobPubKeySpec);
64 * Signature sig = Signature.getInstance("DSA");
65 * sig.initVerify(bobPubKey);
66 * sig.update(data);
67 * sig.verify(signature);
68 * </pre>
69 *
70 * <p> Every implementation of the Java platform is required to support the
71 * following standard {@code KeyFactory} algorithms:
72 * <ul>
73 * <li>{@code DiffieHellman}</li>
74 * <li>{@code DSA}</li>
75 * <li>{@code RSA}</li>
76 * </ul>
77 * These algorithms are described in the <a href=
78 * "{@docRoot}/../technotes/guides/security/StandardNames.html#KeyFactory">
79 * KeyFactory section</a> of the
80 * Java Cryptography Architecture Standard Algorithm Name Documentation.
81 * Consult the release documentation for your implementation to see if any
82 * other algorithms are supported.
83 *
84 * @author Jan Luehe
85 *
86 * @see Key
87 * @see PublicKey
88 * @see PrivateKey
89 * @see java.security.spec.KeySpec
90 * @see java.security.spec.DSAPublicKeySpec
91 * @see java.security.spec.X509EncodedKeySpec
92 *
93 * @since 1.2
94 */
95
96 public class KeyFactory {
97
98 private static final Debug debug =
99 Debug.getInstance("jca", "KeyFactory");
100
101 // The algorithm associated with this key factory
102 private final String algorithm;
103
104 // The provider
105 private Provider provider;
106
107 // The provider implementation (delegate)
108 private volatile KeyFactorySpi spi;
109
110 // lock for mutex during provider selection
111 private final Object lock = new Object();
112
113 // remaining services to try in provider selection
114 // null once provider is selected
115 private Iterator<Service> serviceIterator;
116
117 /**
118 * Creates a KeyFactory object.
119 *
120 * @param keyFacSpi the delegate
121 * @param provider the provider
122 * @param algorithm the name of the algorithm
123 * to associate with this {@code KeyFactory}
124 */
125 protected KeyFactory(KeyFactorySpi keyFacSpi, Provider provider,
126 String algorithm) {
127 this.spi = keyFacSpi;
128 this.provider = provider;
129 this.algorithm = algorithm;
130 }
131
132 private KeyFactory(String algorithm) throws NoSuchAlgorithmException {
133 this.algorithm = algorithm;
134 List<Service> list = GetInstance.getServices("KeyFactory", algorithm);
135 serviceIterator = list.iterator();
136 // fetch and instantiate initial spi
137 if (nextSpi(null) == null) {
138 throw new NoSuchAlgorithmException
139 (algorithm + " KeyFactory not available");
140 }
141 }
142
143 /**
144 * Returns a KeyFactory object that converts
145 * public/private keys of the specified algorithm.
146 *
147 * <p> This method traverses the list of registered security Providers,
148 * starting with the most preferred Provider.
149 * A new KeyFactory object encapsulating the
150 * KeyFactorySpi implementation from the first
151 * Provider that supports the specified algorithm is returned.
152 *
153 * <p> Note that the list of registered providers may be retrieved via
154 * the {@link Security#getProviders() Security.getProviders()} method.
155 *
156 * @implNote
157 * The JDK Reference Implementation additionally uses the
158 * {@code jdk.security.provider.preferred} property to determine
159 * the preferred provider order for the specified algorithm. This
160 * may be different than the order of providers returned by
161 * {@link Security#getProviders() Security.getProviders()}.
162 *
163 * @param algorithm the name of the requested key algorithm.
164 * See the KeyFactory section in the <a href=
165 * "{@docRoot}/../technotes/guides/security/StandardNames.html#KeyFactory">
166 * Java Cryptography Architecture Standard Algorithm Name Documentation</a>
167 * for information about standard algorithm names.
168 *
169 * @return the new KeyFactory object.
170 *
171 * @exception NoSuchAlgorithmException if no Provider supports a
172 * KeyFactorySpi implementation for the
173 * specified algorithm.
174 *
175 * @see Provider
176 */
177 public static KeyFactory getInstance(String algorithm)
178 throws NoSuchAlgorithmException {
179 return new KeyFactory(algorithm);
180 }
181
182 /**
183 * Returns a KeyFactory object that converts
184 * public/private keys of the specified algorithm.
185 *
186 * <p> A new KeyFactory object encapsulating the
187 * KeyFactorySpi implementation from the specified provider
188 * is returned. The specified provider must be registered
189 * in the security provider list.
190 *
191 * <p> Note that the list of registered providers may be retrieved via
192 * the {@link Security#getProviders() Security.getProviders()} method.
193 *
194 * @param algorithm the name of the requested key algorithm.
195 * See the KeyFactory section in the <a href=
196 * "{@docRoot}/../technotes/guides/security/StandardNames.html#KeyFactory">
197 * Java Cryptography Architecture Standard Algorithm Name Documentation</a>
198 * for information about standard algorithm names.
199 *
200 * @param provider the name of the provider.
201 *
202 * @return the new KeyFactory object.
203 *
204 * @exception NoSuchAlgorithmException if a KeyFactorySpi
205 * implementation for the specified algorithm is not
206 * available from the specified provider.
207 *
208 * @exception NoSuchProviderException if the specified provider is not
209 * registered in the security provider list.
210 *
211 * @exception IllegalArgumentException if the provider name is null
212 * or empty.
213 *
214 * @see Provider
215 */
216 public static KeyFactory getInstance(String algorithm, String provider)
217 throws NoSuchAlgorithmException, NoSuchProviderException {
218 Instance instance = GetInstance.getInstance("KeyFactory",
219 KeyFactorySpi.class, algorithm, provider);
220 return new KeyFactory((KeyFactorySpi)instance.impl,
221 instance.provider, algorithm);
222 }
223
224 /**
225 * Returns a KeyFactory object that converts
226 * public/private keys of the specified algorithm.
227 *
228 * <p> A new KeyFactory object encapsulating the
229 * KeyFactorySpi implementation from the specified Provider
230 * object is returned. Note that the specified Provider object
231 * does not have to be registered in the provider list.
232 *
233 * @param algorithm the name of the requested key algorithm.
234 * See the KeyFactory section in the <a href=
235 * "{@docRoot}/../technotes/guides/security/StandardNames.html#KeyFactory">
236 * Java Cryptography Architecture Standard Algorithm Name Documentation</a>
237 * for information about standard algorithm names.
238 *
239 * @param provider the provider.
240 *
241 * @return the new KeyFactory object.
242 *
243 * @exception NoSuchAlgorithmException if a KeyFactorySpi
244 * implementation for the specified algorithm is not available
245 * from the specified Provider object.
246 *
247 * @exception IllegalArgumentException if the specified provider is null.
248 *
249 * @see Provider
250 *
251 * @since 1.4
252 */
253 public static KeyFactory getInstance(String algorithm, Provider provider)
254 throws NoSuchAlgorithmException {
255 Instance instance = GetInstance.getInstance("KeyFactory",
256 KeyFactorySpi.class, algorithm, provider);
257 return new KeyFactory((KeyFactorySpi)instance.impl,
258 instance.provider, algorithm);
259 }
260
261 /**
262 * Returns the provider of this key factory object.
263 *
264 * @return the provider of this key factory object
265 */
266 public final Provider getProvider() {
267 synchronized (lock) {
268 // disable further failover after this call
269 serviceIterator = null;
270 return provider;
271 }
272 }
273
274 /**
275 * Gets the name of the algorithm
276 * associated with this {@code KeyFactory}.
277 *
278 * @return the name of the algorithm associated with this
279 * {@code KeyFactory}
280 */
281 public final String getAlgorithm() {
282 return this.algorithm;
283 }
284
285 /**
286 * Update the active KeyFactorySpi of this class and return the next
287 * implementation for failover. If no more implemenations are
288 * available, this method returns null. However, the active spi of
289 * this class is never set to null.
290 */
291 private KeyFactorySpi nextSpi(KeyFactorySpi oldSpi) {
292 synchronized (lock) {
293 // somebody else did a failover concurrently
294 // try that spi now
295 if ((oldSpi != null) && (oldSpi != spi)) {
296 return spi;
297 }
298 if (serviceIterator == null) {
299 return null;
300 }
301 while (serviceIterator.hasNext()) {
302 Service s = serviceIterator.next();
303 try {
304 Object obj = s.newInstance(null);
305 if (obj instanceof KeyFactorySpi == false) {
306 continue;
307 }
308 KeyFactorySpi spi = (KeyFactorySpi)obj;
309 provider = s.getProvider();
310 this.spi = spi;
311 return spi;
312 } catch (NoSuchAlgorithmException e) {
313 // ignore
314 }
315 }
316 serviceIterator = null;
317 return null;
318 }
319 }
320
321 /**
322 * Generates a public key object from the provided key specification
323 * (key material).
324 *
325 * @param keySpec the specification (key material) of the public key.
326 *
327 * @return the public key.
328 *
329 * @exception InvalidKeySpecException if the given key specification
330 * is inappropriate for this key factory to produce a public key.
331 */
332 public final PublicKey generatePublic(KeySpec keySpec)
333 throws InvalidKeySpecException {
334 if (serviceIterator == null) {
335 return spi.engineGeneratePublic(keySpec);
336 }
337 Exception failure = null;
338 KeyFactorySpi mySpi = spi;
339 do {
340 try {
341 return mySpi.engineGeneratePublic(keySpec);
342 } catch (Exception e) {
343 if (failure == null) {
344 failure = e;
345 }
346 mySpi = nextSpi(mySpi);
347 }
348 } while (mySpi != null);
349 if (failure instanceof RuntimeException) {
350 throw (RuntimeException)failure;
351 }
352 if (failure instanceof InvalidKeySpecException) {
353 throw (InvalidKeySpecException)failure;
354 }
355 throw new InvalidKeySpecException
356 ("Could not generate public key", failure);
357 }
358
359 /**
360 * Generates a private key object from the provided key specification
361 * (key material).
362 *
363 * @param keySpec the specification (key material) of the private key.
364 *
365 * @return the private key.
366 *
367 * @exception InvalidKeySpecException if the given key specification
368 * is inappropriate for this key factory to produce a private key.
369 */
370 public final PrivateKey generatePrivate(KeySpec keySpec)
371 throws InvalidKeySpecException {
372 if (serviceIterator == null) {
373 return spi.engineGeneratePrivate(keySpec);
374 }
375 Exception failure = null;
376 KeyFactorySpi mySpi = spi;
377 do {
378 try {
379 return mySpi.engineGeneratePrivate(keySpec);
380 } catch (Exception e) {
381 if (failure == null) {
382 failure = e;
383 }
384 mySpi = nextSpi(mySpi);
385 }
386 } while (mySpi != null);
387 if (failure instanceof RuntimeException) {
388 throw (RuntimeException)failure;
389 }
390 if (failure instanceof InvalidKeySpecException) {
391 throw (InvalidKeySpecException)failure;
392 }
393 throw new InvalidKeySpecException
394 ("Could not generate private key", failure);
395 }
396
397 /**
398 * Returns a specification (key material) of the given key object.
399 * {@code keySpec} identifies the specification class in which
400 * the key material should be returned. It could, for example, be
401 * {@code DSAPublicKeySpec.class}, to indicate that the
402 * key material should be returned in an instance of the
403 * {@code DSAPublicKeySpec} class.
404 *
405 * @param <T> the type of the key specification to be returned
406 *
407 * @param key the key.
408 *
409 * @param keySpec the specification class in which
410 * the key material should be returned.
411 *
412 * @return the underlying key specification (key material) in an instance
413 * of the requested specification class.
414 *
415 * @exception InvalidKeySpecException if the requested key specification is
416 * inappropriate for the given key, or the given key cannot be processed
417 * (e.g., the given key has an unrecognized algorithm or format).
418 */
419 public final <T extends KeySpec> T getKeySpec(Key key, Class<T> keySpec)
420 throws InvalidKeySpecException {
421 if (serviceIterator == null) {
422 return spi.engineGetKeySpec(key, keySpec);
423 }
424 Exception failure = null;
425 KeyFactorySpi mySpi = spi;
426 do {
427 try {
428 return mySpi.engineGetKeySpec(key, keySpec);
429 } catch (Exception e) {
430 if (failure == null) {
431 failure = e;
432 }
433 mySpi = nextSpi(mySpi);
434 }
435 } while (mySpi != null);
436 if (failure instanceof RuntimeException) {
437 throw (RuntimeException)failure;
438 }
439 if (failure instanceof InvalidKeySpecException) {
440 throw (InvalidKeySpecException)failure;
441 }
442 throw new InvalidKeySpecException
443 ("Could not get key spec", failure);
444 }
445
446 /**
447 * Translates a key object, whose provider may be unknown or potentially
448 * untrusted, into a corresponding key object of this key factory.
449 *
450 * @param key the key whose provider is unknown or untrusted.
451 *
452 * @return the translated key.
453 *
454 * @exception InvalidKeyException if the given key cannot be processed
455 * by this key factory.
456 */
457 public final Key translateKey(Key key) throws InvalidKeyException {
458 if (serviceIterator == null) {
459 return spi.engineTranslateKey(key);
460 }
461 Exception failure = null;
462 KeyFactorySpi mySpi = spi;
463 do {
464 try {
465 return mySpi.engineTranslateKey(key);
466 } catch (Exception e) {
467 if (failure == null) {
468 failure = e;
469 }
470 mySpi = nextSpi(mySpi);
471 }
472 } while (mySpi != null);
473 if (failure instanceof RuntimeException) {
474 throw (RuntimeException)failure;
475 }
476 if (failure instanceof InvalidKeyException) {
477 throw (InvalidKeyException)failure;
478 }
479 throw new InvalidKeyException
480 ("Could not translate key", failure);
481 }
482
483 }